Gas mixer



Patented jan. 26, i926.

1,570,984 PATENT OFFICE.

FRIEDRICH WOLFF, 0F BERLIN, GERMANY, ASSIGNOR T0 SELAS AKTIENGESELL-SCHAFT, 0F BERLIN, GERMANY.

GAS MIXER.

Application eld December 21, 1923; Serial No. 682,078.

To all whom t may concern:

Be it known that I, FRIEDRICH VVOLFF, a citizen of the German Republic,and a resi` dent of Berlin, Germany, have Jinvented certain new anduseful Improvements in Gas Mixers, of which the following is aspecication.

In gas burners or jets as theyare used for industrial purposes theadmission ofthe gases to be mixed, combustible or illuminating gas, airand sometimes oxygen into a common mixing device for the supply of anumber of burners, or into a mixing chamber for the supply of one ormore burners, takes place either under even pressure or under variouspressures in such a manner, that the air is admitted under the greaterpressure and is used to force the gas into the mixing chamber by theemployment of nozzles and injectors.

It is to these types of gas mixing arrangements that my invention bearsspecial reference, and its main object is to eliminate the possibilityof air entering the gas conduit when the pressure in the same happens tofall below a certain amount, or of gas entering the air conduit when thepressure in the latter happens to fall oit. In both these cases thereexists a great risk of danger as explosive mixtures may form in theconduits, in the gas meter or in the compressor, which may easily leadto explosions when the flame should happen to fire back after the burnerhas been ignited.

Since it is very diiiicult to arrange ordinary stop valves for theelimination of these risks, because of the difference in the pressures.between gas and air being normally very small, the said object of theinvention is effectively realized by the provision, withn in theconduits leading to the mixing chamber, of individually controlledspecial stop valves, which will easily respond to even slight variationsin the pressure.

Another object of the invention is the provision of means, in connectionwith the said special stop valves, for enabling a suflicient force beingexercised upon the valve proper on the pressure in the conduits, orconduit, falling below a predetermined minimum.

Another object of the invention consists in the combination of the saidspecial stop valves with such regulating valves for the gas or the air,as they are sometimes used b in this kind of gas mixing arrangements,the arrangement then being such that the actuating organ of theregulating valve may simultaneously be used to serve as the actuatingmember of the said special stop valves also.

Further objects of the invention are the generally improved andsimplified arrangement and combination of parts in gas mix'- ing devicesof the said type as hereinafter more fully described with reference tothe accompanying drawings, in which several modifications of theinvention are illustrated by way of example.

In these drawings,

Fig. 1 is a largely diagrammatic view in part-sectional side elevationof a complete gas mixing arrangement according to the invention,including the burner installation,

Fig. 2 illustrates one form of the special stop valves in verticalsection,

Fig. 3 shows a modified form of the said special stop valve in verticalsection.

Fig. 4 illustrates the combination cf two special sto valves with amixing device for gas an air in part-sectional side elevation.

Referring in particular to Fig. 1, the mixing arrangement consists ofthe gas conduit 1, gas meter 2 which is in connection therewith, airconduit 3 and a compressor 4, the mixing device proper for gas and aiiIconsisting of a nozzle and injector 5 at the connection between gasconduit 1 and air conduit 3, and of the burner 6 for the heat-- ing, forexample, of a tempering forge 6. In the gas conduit 1 and the airconduit 3 the stop valves 7 and 7 respectively are arranged. Each of thesaid stop valves, of which one is shown in Fig. 2 on an enlarged scale,includes a casing 8 having inlet and outlet connections 9 and 10respectively and also includes a regulating valve,

a lever and a diaphragm as hereinafter de-I scribed. Referringpartieularly to Figure 2, 11 is a valve seat adapted to be closed by aregulating valve body 12 which is under the action of a diaphragm 15 bythe intermediary of a two-arm lever 14 rocking about its fulcrum 13.Thel action of the diaphragm may, if desired, be increased by theapplication of a weight 16. Under the inluence of normal workingpressure this dia phragm, which is connected to the lever 14 y means ofa link 14', holds the valve 11,

12 in open position, whereas on the pressure on the admission sidedecreasing below a certain minimum, the said diaphragm and the Weight16, it' such is provided, come into operation and, pressing the link 14downwardly, cause the closing of the valve 11, 12. lt is evident, thatthe diameter ofthe diaphragm should be sufficiently large to ensure suchclosing taking place even at comparatively narrowly limited di'erencesin the `gas or air pressure.

The modication of the salety ldevice for the protection against backfiring vas shown in Fig. 3 differs from the laforesaid in .that thevalve 12a with its -connected diaphragm is directly combined with aregulating valve iior `the gas or air pressure. As in the -lormerexample, 8 denotes the valve casing, 9a the entrance and 10 the exitrior the gas or air respectively, and 11a is the valve seat adapted tobe closed bythe valve 12a which, by means ot lever 14, fulcrumed at 13a,is under the influence of the controlling diaphragm 15a. ln connectionwith the said diaphragm, as by means or' a yvalve rod 1", is a valvecone 19 adapted to control .the valve passage 18. From the drawing (Fig.3) it will be evident,'that the adjustment of the regulating valve cone19 depends on the extent `or degree of curvature oi' the diaphragm 152Lwhich, in turn, depends on the pressure ot the gas or air admittedthrough. .the conduit. According to the amount'ol' this pressure theeffective valve opening 18 will be more or less .throttled. The valve12a olf the special `stop valve (Fig. 3), on the other hand, is sodisposed with regard to its seat 11a that the mere regulation liftsofthe valve 19 `will always leave suliicient clearness between the valve12a and its seat to prevent tlirottling influence on the gas current.Should the regulating v-alve 19- with falling pressure open beyond apredetermined amount, so that there would be a risk of air entering'from the air conduit into the casing '8u and the gas conduit 1, thevalve 12a would close down on its seat and thus prevent the danger ot'the formation of an explosive mixture within the gas conduit.

In the arrangement according .to Fig. f1 the two stop valves 7 and 7 forthe passage of air and gas in combination with regulat ing valves suolias shown in Fig. 3 areillustrated as being joined to a mixing .device20, into which they deliver gas and air respcctively. The said mixingdevice consists of aichamberQO comprising aislide valve 22 which isactuated bythe vibrations of a diaphragm 21, and by means of which thecalibrated admission openingsQB and 24 are controlled so that the mixingratio of gas to air always remains constant. The ligure shows the slidevalve 22 of the mixing de vice in its working position. As soon as gasand air enter under pressure this slide valve moves to cover.theipor-tsQ- and Qa `until the v.pressure in the conduit 125 for lthemixture has attained the'amount which is determined by :the -weight ofthe slide valve Q2 and the diameter or :the diaphragm. In 'the vordinary7 position, however, the `ent 'ance rports for gas and air arecompletely open.

lWhat I claim is 1. ln a mixing ,arrangemenn a gas conduit and an 4airconduit introducing gas and air under pressure, a mixing device to whichsaid conduits lead, za .stop `valve in each ot 4the `said conduits, each`stop valve including a casing forming part of one of the said conduits4and also including a ydiaphragm vin said casing and acted upon by thepressure lin the yconduit on one side, and by atmospheric pressure onthe lother side, a regulating valve, a two-arm vlever between theregulating valve and the-associated diaphragm, and links to connect oneend of the said two-arm lever to the regulating valve, andthe other tothe diaphragm so a-s to close the regulating valve on the pressure in.one ot theconduits falling below a certain amount.

ln gas mixing arrangement 'having gas .and .air conduits,the combinationwithin each ot the said .conduits of a stop valve, a pressureregulatingvalve, a valve, a commen pressure responsive element, all arranged in -acasing, with a `mixing chamber in connection with each of the said stopvalves, a pressure responsive element in the said mixing chamber, and aslidable member 'in thesaid .chamber actuated by the said pressureresponsive element so as to open the admission ports for gas and airwhen the device is at rest, and to partially close same when at workuntil balance is established between the working pressure on one side oithe said element and the atmospheric pressure on the other side.

ln witness l whereof I -aliix my signature.

FRIEDRICH WOLFF.

